Sudoku Scan&Solve is made for helping you solving Sudoku puzzles. It scans Sudokus from paper or images, recognizing machine written numbers, and being able to learn handwritings as well. Having scanned a Sudoku you can let it solve single cells, rows, columns or 3x3 boxes, tell you where a number is in a row, column or box, or solve the puzzle as a whole. As Sudoku Scan&Solve can also create Sudokus, you can also just use it as a simple Sudoku App that always tells you if you've made a mistake and helps you when you get stuck.
You can get it here: